Automatic call distribution systems are known. Such systems are typically used as a means of distributing telephone calls among a group of agents of an organization. While the automatic call distributor (ACD) may be a separate part of a private branch telephone exchange (PBX), often the ACD is integrated into and is an indistinguishable part of the PBX.
Often the organization disseminates a single telephone number to its customers and to the public in general as a means of contacting the organization. As calls are directed to the organization from the public switched telephone network (PSTN), the automatic call distribution system directs the calls to its agents based upon some algorithm, typically based upon availability. For example, where all agents are considered equal, the ACD may distribute the calls based upon which agent position (telephone) has been idle the longest time.
In order to distribute incoming calls from the PSTN to the available agents, the interaction of a controlling computer with a switching fabric of the PBX and ACD becomes essential. Often a connection to a local PSTN is in the form of a number of trunk connections. Each of the trunk connections is monitored by the controller for incoming calls. Where a call is detected, the controller searches for and selects an idle agent. Upon selecting an agent, the controller commands the switch to form a connection between the incoming trunk and selected agent.
In more complicated systems, the organization may use a number of telephone numbers to identify different individuals and functions within the organization. Each telephone number may be assigned to a particular incoming trunk or group of incoming trunk lines. As such, the controller may be required to recognize a call target based upon an identity of an incoming trunk line and route the call accordingly.
In other systems, the ACD of an organization may receive calls directed to different call targets over the same trunk lines. In such a case, the call target may be identified to the ACD by a pulse code modulated (PCM) signal transferred from the PSTN to the controller of the ACD by a dialed number identification service (DNIS) operating from within the PSTN.
In systems associated with service organizations, where many calls are received and handled by many agents, it may be important for an agent to have ready access to customer files. In such a situation, a database is maintained of existing customers. Customer records may be displayed on agent terminals as the agents converse with specific customers. In some cases, the customer may be identified to the database for display of records on the terminal by the agent entering a customer identifier into a keyboard associated with the terminal. Alternatively, the controller of the ACD may transfer an identifier of the customer to the database based upon an automatic number identification (ANI) facility, operating from within the PSTN.
Where ANI is used, the controller of the ACD receives the ANI digits (identifying the caller via the caller's telephone number) at the same time the call arrives from the PSTN. Upon selecting an agent, the controller may transfer the call to a queue for the selected agent or directly to the selected agent. At the same time that the call is delivered to the agent, the controller sends an identifier of the selected agent and ANI number of the customer to a controller of the database (the host). The host, in turn, displays the customer records via a computer monitor of the selected agent at the same time the call is delivered.
As a further feature, calls may be transferred among agents. Where a first agent finds that he or she cannot help a particular customer, the agent may activate a key on a keyboard of the agent and enter an identity of another agent or agent group that may be better able to help the customer. The controller of the ACD may immediately connect the call to the newly identified agent, or may place the call in a queue until the identified agent becomes available.
In either case, the controller transfers a message to the host identifying the previous and newly identified agent. Since the host knows the identity of the customer displayed at the terminal of the previous agent, the host may now display those same customer records at the terminal of the newly selected agent.
Where a call is placed in a queue, the ACD controller may monitor a total time that the call has been in the queue. Where the time exceeds a threshold value, the controller may transfer (overflow) the call to a newly selected agent at another less heavily loaded ACD (overflow ACD) within the same organization. The controller of the transferring ACD transfers DNIS and ANI information as well as a call sequence number assigned by the transferring ACD to the overflow ACD. The overflow ACD, upon receiving the call, transfers the information to the host including an identifier that the call is an overflow call. The host in turn then polls each ACD to identify the transferring ACD and any recently created call records generated by the transferring ACD.
While the existing method of ACD operation is relatively satisfactory, it is dependent upon a record of connection transactions as a method of identifying a call to the host. Where a connection to an agent is completed, a transaction identifier is sent to the host memorializing the transaction. The record of the connection is placed in a call record held in an area reserved for the transferring ACD. Where a call is received and placed in a queue for delivery to the next available agent, a call arrival message is sent to the host and saved in the transferring ACD's record area. Where the call is then transferred to another ACD, there is no means for directly identifying the call record created by the transferring ACD. As a consequence, the host must poll (i.e., search the call records of) each ACD to identify the call record of the call. Where a host serves many ACDs, a considerable amount of time may be lost searching for call records. Accordingly, a need exists for a better method of tracking overflow calls among ACDs.